Sorry, while Unions may serve a role in blue-collar jobs, I don't agree that they have much of a place it IT jobs. Especially when it comes to protectionism and "seniority". I work at a public university and our IT is unionized. It is basically impossible to fire the old IBM mainframer who refuses to learn anything new because he is retiring in 5-10 years and pines for the old days. So in these difficult budget times, we have to lay off the young, productive staff and are stuck with the useless ones.
As is probably typical in the unionized government sector, if you could pick and choose the 20% to lay off, you would save a ton of money and productivity would probably go UP! As it is, you get rid of the modern, young talent and productivity actually goes down far more than the 20% you are laying off.